Remove support for ubuntu-20.04

* It's gone: actions/runner-images#11101

Add jruby-10.0.0.0

Update CRuby releases on Windows

Add ruby-3.4.3

Merge pull request #737 from ruby-builder-bot/windows

Update CRuby releases on Windows

Update CRuby releases on Windows

Add ruby-3.1.7,ruby-3.2.8

Add truffleruby-24.2.0,truffleruby+graalvm-24.2.0

Use $JAVA_HOME/bin/java for the check

Test successful JRuby start without using launcher

Native launcher appears to hang on GHA when the JDK version is too
old for JRuby 10. This bypasses it and should be a bit lighter. It
will also avoid any variability in the launcher used, since Unixes
and Windows already use different executables.